Articulated conveyer for mining machines



July 28, I953- Q R. c. Luflpouls r 2 64 7 ARTICULATED c'pnvmak FOR uinmc MACHINES 6 Sheets-Sheet l Filed Oct. 12, 1951 y 8, 1953 R. c. LUNDQUIST 2,646,871

ARTICULATED CONVEYER FOR MINING MACHINES Filed Oct. 12, 1951 6 Sheets-Sheet:5

12 3+ 4 t6 93 g J01 61 2;? p I v z mm I A R. c. LUNDQUIST 2,646,871-

ARTICULATED comm FAB MINING MAcHmEs 6 Sheets-Sheet 6 July 28, 1953 Filed Oct. 12, 1951 L as Patented July 28, 1953 UNITED STATES ARTICULATED CONVEYER FOR, MINING MACHINES Richard C. Lundquist, Chicago, Ill., assignor to Goodman Manufacturing Company, Chicago, Ill., a corporation of Illinois Application October 12, 1951, Serial No. 251,075

This invention relates generally to improvements in machines for conveying material and more particularly to improvements in devices for taking up the slack in an endless chain flight conveyor occasioned by the articulation of the conveyor sections with respect to each other.

Machines for gathering and loading material in underground mines have been characterized by the use of chain flight conveyors for moving the material from the gathering head to the discharge end of the discharge boom. Both the discharge boom and the gathering head are arranged to articulate with respect to the main frame portions of the machine, and in such articulation undue slackening of the chain conveyor has occurred, such slackening being caused by the shorter length of travel necessary for the chain flight conveyor to describe in positions of articulation of the discharge boom and the gathering head, more particularly the discharge boom.

8 Claims. (Cl. 198109) According to the present invention use is made of the articulating movement of the discharge boom to vary the position of an idler roller having the chain flight conveyor trained therearound, the shaft supporting the idler roller moving in an extensible direction which varies depending upon the amount of articulation. The shift in position of the idler roller is achieved by a carriage and sheave assembly abutting the idler shaft, the sheaves having a flexible strand trained therearound so arranged as to move the carriage and the idler shaft in an extensible direction as increased swinging movement of the discharge boom takes place. The ends of the flexible strand are anchored to sliding blocks or plates disposed near the discharge end of the boom, which sliding plates are moved by pusher members moving with respect to the boom as swinging movement thereof takes place.

The invention, while not so limited, is particlarly adapted for use in a discharge boom for an articulated conveyor of a material gathering and loading machine of the kind as disclosed in an application of Robert A. McC'allum, Serial No. 253,245, filed October 26, 1951, for improvements in Rear Boom Support for Loading Machines. I

With the foregoing considerations in mind it 'is a principal object of this invention to afford a new and improved slack take up device for an articulated conveyor.

Other objects and important features of the invention will be apparent from a study of the following description taken with the drawings 2 which together illustrate a preferred embodiment of the invention, and what is now considered to be the best mode of practicing the principles thereof. Other embodiments of the invention will be suggested to those having the benefit of the teachings herein, and it is therefore intended that the scope of the invention not be limited by the precise embodiment shown herein, and only by the spirit and scope of the appended claims.

In the drawings:

Fig. 1 is a' general plan view of a material gathering and loading machine having embodied therein a slack take up device according to the present invention;

Fig. 1A is a side View thereof;

Fig. '2 is an isometric view of the discharge boom and the slack take up device of the material gathering and loading machine shown in Figs. 1 and 1A;

Fig. 3 is a plan view of the discharge boom shown inFig'. 2, showing certain details of construction of the slack take up device;

Fig. 4 is a more detailed plan view of the slack take up device shown in Figs. 2 and 3;

Fig. 5 is a View similar to Fig. 4 but showing the position of the slack take up device when the discharge boom is in the straightaway position seen' in Fig. 2;

Fig. 6 is a section taken along the line 6-45 of Fig. 4, showing certain details of the carrier assembly for the slack take up device and the ar rangement'of an idler sprocket thereon;

Fig. 7 is a longitudinal sectional view, taken along line 11 of Fig. 5, certain parts thereof being shown in side elevation, showing certain details of the support for the movable carrier assembly for adjusting the position of the idler roller;

Fig. 8 is a transverse sectional view taken along the line 88 of Fig. 5 looking in the direction of the arrows and showing certain other details of the movable carrier assembly;

Fig. 9 isa perspective View of a side plate for moving the flexible chain seen in Figs. 4 and 5.

and also showing a guide for supporting and guiding the movable side plate;

Fig. 10 is an isometric View of the movable carrier assembly for moving the idler and take up roller seen in Figs. 2, 3, 4 and 5;

Fig. 11 is an isometric view of a fixed shoe mounted in the discharge boom and adapted to support the movable carriage;

Fig. 12 is a transverse sectional view taken along the line l2l2 of Fig. 5 and looking in the direction of the arrows, certain details of the idler and take up roller being shown in elevation view;

Fig. 13 is a more or less schematic view of the discharge boom shown in Figs. 2 and 3, showing the position of the support links and the support arms when the discharge boom is in the straightaway position;

Fig. 14 is a view similar to Fig. 13 showing the shift of the sup-port arms relative to each" other upon articulation of the discharge-boom;

Fig. 15 is a view similar to Fig. 14, showing schematically the shortened length of travel required of the chain flight conveyor in "moving past the point of articulation of the 'dischargeboom, and showing the relative movement of the support arms in swinging thewdischargeboom to the position shown in Fig. 15; and

Fig. 16 is a perspective view of the idler'and take up roller shown inFigs. 4, and 12. Referring particularly to" Figs. l,-lA, 2 and 3 of the drawings, the present invention is shown as embodied in a gathering aridloading machine indicated generally by the reference numeral 2% Such amachine may consist of a main frame 2! mounted upon crawler treads 2 2 which are supplied with motive powerby electric motors 23 mounted on-each side of the-main frame 2!,

each of said motors being-adapted independently to supply power to the individualcrawlertreads 22. Said machine includes a gathering head 2 adapted to swivel with respect to the mainframe 2i in both a vertical-and horizontal direction to the positions shown in phantom outline seen in Figs. 1 and 1A. Material gathered by the gathering head 24 is moved by a zconveyor 25 of the chain flight type, the :conveyor 26 moving 1ongitudi'nally along a swivelable trough portion 2?,

a fixed main: trough portion 2.8, a vertically movable trough portion 29 and a discharge boom-portion 3! whence. the" chain .iflight conveyor is trained around an idler :roller 32 in the fashion known in the art.

The vertically movable trough section 28 is adapted to be raised-and lowered by lifting cylinders 33 mounted Onseachsideof the trough 'portion 28, and the' discharge boom- 3| is adapted to pivot about a point of articulation '34 by fluid operated motors 35 mounted under thedischarge boom section 3!- and' the vertically LmOvalole trough portion 23 and' extending across the point of articulation' l. Then-discharge boom portion 3| is thus adapted to move .in a verticalrplane to positions as shown inphantom outline i-n-Fig.

1A and to positions :in a horizontalplane aseseen in phantom outline in Fig. 1.

The general details of-construction of -such a gathering and loading :machine may be inpart as disclosed in Cartlidge Patent No. 2,388,385, issued November 6, l95, for. flvlaterial Gathering, and Loading Machine.

As seen with particular reference to Figs. 2 and 3 the chain conveyor-thus moves longitudinally of the vertically movable trough section 28 and the discharge boom .31 past the point of articulation 34 and around the idler roller 32,

which is mounted'upon-a dead shaft 3.! movable in a slot 33 nearlthe dischargeend of the .-discharge boom 3|.

The vertically movable trough section 29 .con-

sists of an upper chain-support plate 39, and a lower chain support plate,-not shown, whichare flanked by vertical side plates 4l.- As seen in more detail with respect to :an application of Robert A. McCallumpSerialNo. 253,245,-fi1ed extending horizontal .fiange 46. port plates 42 and as and the chain support I plates of the vertically movable trough portion side plates ll gudgeon members 58, having hingedly connected support plate t2 and a lower chain support plate 33 similarly spaced vertically from each other to provide clearance for the return run of the chain .iiight conveyor 2%. The sides of the spaced chain support plates 42 and 43 are welded to a vertical leg M.- of an angle member having an outwardly The chain sup- 29..are cut .on an are d! with the pivot point 34 as a center so that a smooth surface will be presented for both the forward and return runs of the chain flight conveyor 28 in all positions of articulation of the discharge boom 3| with respect to the vertically movable trough portion 23.

- The vertical leg at is welded to plates 45 formthe discharge end of the discharge boom 3?. The plates t8 are provided with stiffener flanges 4S and 5!, the plate 48 being provided with the slot for support of the dead shaft 3! or" the idler roller 32. The plates 48 are additionally secured to the vertical leg 44 by straps 52 welded to the inside faces of the vertical plates 48.

The. discharge boom 3| turns upon a pivot bearing indicated generally by the reference numeral 35, said pivot bearing 65 being supported on a spider 53, see Fig. 3, which is welded to the underside of the bottom support plate, not shown, of the verticallymovable trough section .29. Details of the pivot bearing 45 are more clearly shown with reference to the aforesaid McCallum application. The spider 53 has arms 5 welded to brackets 56 for the raising and lowering cylinders 33,.the brackets 53 being secured, as by welding, to the underside of .the vertically movable trough section. 28.

In order to maintain the pivot bearing 45 free from thrusts incident to the weight of the discharge boom 3i, and to maintain the power means 36 for swinging the boom 35 in a position beneath both the discharge section 3! and the vertically movable trough section 29, means are provided for supporting the discharge boom I To this end the weight of the discharge boom 3i is'taken by the vertical side plates ii of the vertically movable trough section 29, and as seen with particular reference to Figs. 2 and 3 vertical are additionally stiffened by thereto load support links 55, the loads on the .links 55 being taken by vertical hinge pins 60.

The load supporting links 55 extend across the point or axis of articulation 35 of the discharge boom 3! on each side thereof, and are hingedly connected to gudgeon members 57 :by vertical hinge pins 58. The gudgeons 5'1 are welded to the ends of channel shaped load supporting arms 59 which are in bearing engagement with the underside of thehorizontal flanges 46, the channels 59 being-guided by angle members 5! having a vertical leg 62 welded to the flange 35 and a turned in flange 63 welded to the vertical leg :24 on the outside faces thereof to define -a box section for guiding the channel members 59.

Each of the load supporting links 55 is provided with feet 55 having a chain-flight-engaged surface 64 which fairs back toward the gudgeon member 50, and a chain flight engaged surface 66 which fairs back to a chain flight guide plate '61, which is movable with the load supporting arm 59 and guided by an angle shaped guide 83 secured to the top of the flange 46, the guide 68 having a downward extending leg 69 which is spaced from the inside face of the vertical leg 44 of the support angle.

As the discharge boom 3! is moved articulately with respect to the vertical movable portion 29, about the pivot bearing 45, the support links 55 will move to positions as indicated generally in Fig. 3, the chain flight surfaces 54, 55 and 65 engaging the ends of the chain flights on the "inside of the curve thus effecting a gradual change in direction of the chain flight conveyor 26. In such movement of the discharge boom 3|, the load support arms 59 move telescopically within the box section defined by the vertical angles 44 and the angles 51, one of said load support arms 59 moving toward the end of the discharge boom 3| in such telescopic movement, the opposite load supporting arm 59 being withdrawn from the discharge end of the discharge boom, the guide plates 61 on each side of the discharge boom section 3| being concomitantly guided by the guides 68 and moving with their associated load supporting arms 59.

According to the present invention, the telescopic movement of the load supporting arms 59 just described is employed to vary the position of the idler roller 32 so that the slack in the chain flight conveyor 25 occasioned by the shorter length of travel required when moving past the pivot point 34 in a position, for example, as seen in Fig. 3, is taken up by moving the idler roller 32 toward the discharge end of the discharge boom 3 I. As seen in Fig. 15, the chain flight conveyor 26 in moving past the pivot point 34 may be considered as describing a curve having approximately a length C with two tangents each of length T. In the straightaway position of the discharge boom 3| with respect to the vertically movable trough 29 as seen in Fig. 13, the chain flight conveyor 26 may be considered as moving through a distance equal to twice the length of the tangent T, while in the position seen in Fig. 15 in describing the approximate curve C, the amount of slack developed in the chain flight conveyor may be considered as 2TC', which must approximately equal within satisfactory limits the movement of the idler roller 32 toward the discharge end of the discharge boom 31. The movement to the position as in Fig. 15 is accompanied by a relative movement of the two load supporting arms 58 with respect to each other, which movement is equal to twice the amount of travel of the pistons of the fluid motors 36 accomplishing such movement, see also Fig. 1A. This relative movement of the load supporting arms 59 is employed to control the movement of the idler roller 32 so that it will have a movement approximating the value 2TC.

As seen with particular reference with Figs. 4, 5, and 11, the upper chain support plate 42 is provided with an opening 11 to receive a shoe 12, see also Fig. 11, which is welded into position with a top surface 13 of the shoe 12 flush with the top surface of the upper chain support plate 42. The shoe 12 is formed with a clevis 14 to receive an idler roller held in position to the clevis 14 by a pin 11. The shoe 12 is formed With guides 18 on each side thereof spaced below the underside of the upper chain support plate 42 to provide a guideway for a movable carriage 15, see Fig. 10. A movable plate 80, see Figs. 4, 5, 7 and 8, rests upon a top plate 18 of the movable carriage 15 and is interposed between said top plate 18 and the underside of the upper chain support plate 42. The movable plate 80 is Welded to a pair of semi-cylindrical members which overlie and embrace the idler roller shaft 31 and which are positioned on each side of the roller 32 in such a fashion that upon extensible movement of the roller shaft 31 there will be no gap between the end of the upper chain support plate 42 and the idler roller shaft 31. The movable plate 80 thus provides a surface over which material may be moved by the chain flight conveyor 26. The carriage 15 is formed of the upper plate 18 having a slot 19 therein so that the carriage 15 is guided by the shoe 12 and the guides 16 and the underside of the upper chain flight support plate 42.

A pair of roller support plates 3! are disposed on each side of the slot 19 and are spaced below the upper plate 18, and are held in spaced relationship with respect to the upper plate 13 by vertical webs 82 Welded. respectively to the upper plate 18 and the roller plates ti, see also Fig. 8. Blocks 83 are Welded to the upper carriage plate 18 and also to the roller support plates 8! and a vertical web 3t is welded to the spaced blocks 83. The blocks 83 are each tapped to receive bolts 85 having heads 81 which bear against flat surfaces 88 formed on the idler roller shaft 31. As seen with particular reference to Figs. 4 and drollers "89' are mounted to turn between the upper carriage plate 13 and the lower roller plates 8| upon pin shafts 9 l A flexible chain 92 is trained around the rollers 89 and the idler roller 16 as seen more clearly with reference to Figs. 4 and 5, and the opposite ends of the chain 92 are fastened as at 93 to a lug 94 extending through the slot 38 in the vertical plate 43 and welded to a sliding plate 96 guided along the outer side of the vertical plates 48. As seen also With reference to Fig. 9 the sliding plate 58 is formed with a rectangular slot 91 extending substantially for the length thereof, which slot 91 is adapted to cooperate with a guide 98 having a T-shaped cross-section and held in position to the outside of the plate 8 by cap screws 93. As seen particularly with reference to Figs. 4 and 5, the slide 96 is adapted to becontacted by the ends of the channel shaped support arms 59 at the ends thereof nearest the discharge end of the discharge boom 3! when the discharge boom 3! is in the straightaway position seen in Fig, 5. The ends of the support arms as are provided with additional contact members it! to insure that the end of the sliding shoe 56 is maintained in contact with the end of the load support arms 59 upon swinging movement of the discharge boom 3|.

As seen with particular reference to Fig. 8, the movable carriage15 is supported additionally upon flange-like extensions from the inside faces of the vertical plates 48 adjacent the end of the discharge boom 3!. The flanges 90 also serve to maintain the carriage 15 in position away from interference by the return run of the chain flight conveyor 26, and as also seen in Fig. 6 the roller plates 8| of the movable carriage 15 are also guided and supported upon flanges Hill extending from the inside of the vertical legs 44 also prevent-ingiinterfenence with the -.carriage 15 by the return run of the: chain flight conveyor .26.

As previously described withref erence to Fig. 15., themovablecarriage i is adapted to move in extensible direction to move the idler roller 32 outwardly to'ta-ke up the-slack inthe chain flight conveyor occasioned by articulation of the discharge boom 34. The articulation thereof is gen- .erally limited to a total :swing of about 450 to either side of thecenter line ofthe gathering and loading machine 2i3,and for all positions of such articulation the carriage will move approximatelyone-four-th of the total travel of one of the load supporting arms 5S.- It will be noted from Fi 5 that the lugs :SQ-are' disposed .at the inner end of the slot 38 when the discharge boom 3-! is in the straightaway-position. .As the boom 3| moves articulately to the position seen in Fig. 4 one of the lugs M and its associated slide 95 will be held in positionat the end of the slot 38, the .end of the support arm 59 thereat withdrawing from the inner end of the slide 96, while the other slide 96 will be moved by its associatedarm 59. 'The arrangement of the single fixed pulley H3 and the pair of movable pulleys 88 mounted on the movable carriage '55 together with the flexible chain 92 trained therearound thus provides for approximately one unit of movement of the carriage '15 for four units of movement along the length of the flexible chain. Such an approximation of movement of the carriage will serve to maintain the proper amount of take up of the slack in the chainfllght conveyor 23 in all positions of articulation of the discharge boom 3 i.

From the description foregoing it will be apparent that a simple and effective device has been provided for taking up the slack in the chain flight conveyor occasioned by articulation of the discharge boom. In the embodiment of the invention described herein use is made of the relative movement of a pair of load supporting arms for a cantilever mounted-discharge boom of a material gathering and loading machine such as is commonly employed in mining underground. While the slack take up device according to the present invention is particularly adaptable to such form of a material gathering and loading machine as is more clearly described and claimed in the aforesaid McCallum application, the slack take up device may quite readily be used in connection with other forms of articulating trough sections of any articulated conveyor, there being necessary in suchcase, however, m ans for providing relative movement between members mounted on the discharge boom so as to provide movement of two members fixed to the end of the chain trained around the fixed pulley and the movable sheaves. While the invention has been described with the use of a chain trained around movable pulleys and a fixed pulley, it is obvious that any flexiblestrand may be employed and trained around a pair of movable sheaves and a fixed pulley.

While the invention has been described in terms of preferred embodiment thereof which it has assumed in practice, the scope thereof is not intended to be limited by the precise. embodiment described herein, other embodiments being capable of modification by those skilled in the art, and it is intended therefore that the invention be limited only by the terms of the claims here appended.

I claim:

1. In an articulated conveyor, a pair of aligned trough-sections; one of said trough sections being movable with respect to the other about a :sub'

-stantial1y vertical axis, each of said trough sections having substantially vertical side walls with vertically spaced upper and lower support plates extending between said vertical side walls for the forward and return runs of an endless conveyor extending longitudinally of said trough sections, an idler mounted at one end of said movable trough section, a pair of support arms 1 hingedly connected to the other trough section .saididler in a direction to take up the slack in saidconveyor occasioned by the articulation of said trough sections, a pulley mounted on said support shoe, a pair of pulleys mounted on said movable carriage, sliding members guided by the side walls of said movable trough section, one or" said sliding members being in contact with theend of one of said support arms during articulation of said trough sections, a flexible strand trained around said pulleys and connected at each end to said sliding members for moving said carriage in a direction to adjust the position of idler upon telescoping movement of said support arms in accordance with the amount of articulation of said trough sections.

2. in an articulated conveyor, a pair of aligned trough sections, one of said trough sections being movable with respect to the other about a substantially vertical axis, each of said trough sections having substantially vertical side walls with vertic lly spaced upper and lower support plates extending between said vertical side walls for the forward and return runs of an endless conveyor extending longitudinally of said trough sections, an idler mounted at one end of said movable trough section, a pair of support arms hing dly connected to the other trough section and in bearin contact with the movable trough section for support thereof in all positions of articulation thereof, said support arms being adapted to move telescopically with respect to said movable trough section during articulation, a support shoe secured to the upper support plate of said movable trough section and a carriage movable on said support shoe longitudinally or said movable trough section, said movable carriage contacting said idler and being adapted to move said idler in a direction to take up the slack in said conveyor occasioned by the articulation of said trough sections, a pulley mounted on said support shoe, a pair of pulleys mounted on s d movable carriage, and a flexible strand trained around said pulleys and 'ing an operative connection with said support arms for moving said carriage in a direction to adjust the position of said idler in accordance with the amount of articulation of said trough sections.

3. In an articulated conveyor, a pair of aligned trough sections, one of said trough sections being movable with respect to the other about a substantially vertical axis, each of said trough sections having substantially vertical side walls with vertically spaced upper and lower support plates extending between said vertical side walls forthe forward and return runs of an endless conveyor extending longitudinally of said trough sections,

an idler mounted at one end of said movable trough section, a pair of support arms hingedly connected to the other trough section and in bearing contact with the movable trough section for support thereof in all positions of articulation thereof, said support arms being adapted to move telescopically with respect to said movable trough section during articulation, a support shoe secured to the upper support plate of said movable trough section and a carriage movable on said support shoe longitudinally of said movable trough section, said movable carriage contacting said idler and adapted to move said idler in a direction to take up the slack in said conveyor occasioned by the articulation of said trough sections; and an operative connection between said carriage and said support arms for moving said carriage in a direction to adjust the position of said idler in accordance with the amount of articulation of said trough sections.

4. In an articulated conveyor, a pair of aligned trough sections, one of which is movable with respect to the other in a substantially horizontal plane, an endless conveyor extending along said troughs, an idler mounted at one end of said swingable trough section, a pair of support arms hingedly connected to the other of said trough sections and in bearing contact with the swingable trough section for support of said swingable trough section in all positions of articulation thereof, said support arms being adapted to move telescopically with respect to said swingable trough section during articulation thereof, a support and a pulley turning thereon mounted in fixed position on said swingable trough section, a carriage movable with respect to said support and supported, said movable carriage being adapted to contact said idler and move said idler in a direction to take up the slack in said conveyor occasioned by the articulation of said trough sections, a pair of pulleys mounted on said movable carriage, and a flexible strand trained around said pulleys and having an operative connection with said support arms for moving said carriage in a direction to adjust the position of said idler in accordance with the amount of articulation of said trough sections.

5. In an articulated conveyor, a pair of aligned trough sections, one of which is movable with respect to the other in a substantially horizontal plane, an endless conveyor extending along said troughs, an idler mounted at one end of said swingable trough section, a pair of support arms hingedly connected to the other of said trough sections and in bearing contact with the swingable trough section f-or support of said swingable trough section in all positions of articulation thereof, said support arms being adapted to move telescopically with respect to said swingable trough section during articulation, a fixed pulley mounted on said movable trough section, a carriage movable with respect to said fixed pulley and said movable trough section, said movable carriage contacting said idler and adapted to move said idler in a direction to take up the slack in said conveyor occasioned by the articulation oi said trough sections, at least one pulley mounted on said movable carriage, and a flexible strand trained around said pulleys and having an operative connection with said load supporting arms for moving said carriage in a direction to adjust the position ofsaid idler in accordance with the amount of articulation of said trough sections.

6. In an articulated conveyor, a pair of aligned trough sections, one of which is movable with respect to the other in a substantially horizontal plane, an endless conveyor extending along said troughs, an idler mounted at one end of said swingable trough section, a pair of support arms hingedly connected to the other of said trough sections and in bearing contact With the swingable trough section for support of said swingable trough section in all positions of articulation thereof, said support arms being adapted to move telescopically with respect to said swingable trough section during articulation, a movable carriage contacting said idler and adapted to move said idler in a direction to take up the slack in said conveyor occasioned by the articulation of said trough sections, and an operative connection between said carriage and said support arms for moving said carriage in a direction to adjust the position of said idler in accordance with the amount of articulation of said trough sections.

7. In an articulated conveyor, a pair of aligned trough sections, one of which is swingable with respect to the other in a substantially horizontal plane, an endless conveyor extending along said troughs, an idler mounted at one end of said swingable trough section, a pair of members adapted to move telescopically with respect to said swingable trough section, a support and a flexible strand guide mounted thereon mounted in fixed position on said swingable trough section, a carriage movable with respect to said support and supported thereby, a pair of flexible strand guides mounted on said movable carriage, and a flexible strand trained around said flexible strand guides and having an operative connection with said telescoping members for moving said carriage in a direction to adjust the position of said idler in accordance with the amount of articulation of said trough sections.

8. In an articulated conveyor, a pair of aligned trough sections, one of which is swingable with respect to the other in a substantially horizontal plane, an endless conveyor extending along said troughs, an idler mounted at one end of said swingable trough section, a pair of members adapted to move telescopically with respect to said swingable trough section, a movable carriage contacting said idler and adapted to move said idler in a direction to take up the slack in Said conveyor occasioned by the articulation of said trough sections, a guide for a flexible strand mounted on said movable trough section, a pair of guides for a flexible strand mounted on said movable carriage, and a flexible strand trained around said guides for said flexible strand and having an operative connection with said telescoping members for moving said carriage in a direction to adjust the position of said idler in accordance with the amount of articulation of said trough sections.

RICHARD C. LUNDQUIS-T.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,388,385 Cartlidge Nov. 6, 1945 2,527,452 Rose Oct. 24, 1950 FOREIGN PATENTS Number Country Date 974,530 France Feb. 23, 1951 

